We plan to isolate the genes which encode the murine T-cell receptor for antigen. We will employ three independent approaches. First, we will screen libraries containing T-cell DNA cloned into an expression vector with serological reagents to detect clones expressing the cell-surface markers I-J, Tsu, and CGAT(an idiotypic determinant). Second, we will determine the amino acid sequence of polypeptides from factors secreted by T-suppressor hybridomas. These protein sequences will be reverse translated into DNA sequence and synthetic DNA probes will be synthesized and used as primers or as DNA probes to screen appropriate cDNA libraries. Finally, we intend to identify gene sequences in cloned T cells which undergo DNA rearrangements. Some of these rearranged sequences may be T-cell receptor genes. Once DNA probes for the T-cell receptor have been obtained, we will characterize the corresponding genomic clones with regard to structure, organization, rearrangements, and diversification.